Summary
CVE-2026-101301 is a vulnerability in the WPCode – Insert Headers and Footers + Custom Code Snippets – WordPress Code Manager plugin. It allows unauthenticated attackers to bypass snippet execution by triggering safe mode. The vulnerability affects plugin versions before 2.4.0. A patch is available in version 2.4.0, and a Proof of Concept (PoC) is scheduled for public release.
Affected and patched versions
WPCode – Insert Headers and Footers + Custom Code Snippets – WordPress Code Manager (plugin insert-headers-and-footers): affected before 2.4.0; fixed in 2.4.0
Is my site vulnerable?
To determine if your WordPress site is affected by CVE-2026-101301, you need to check the version of the WPCode – Insert Headers and Footers + Custom Code Snippets – WordPress Code Manager plugin installed on your site. This vulnerability affects all versions of the plugin before 2.4.0.
Follow these steps to check your plugin version:
Log in to your WordPress administration dashboard.
Navigate to the "Plugins" menu item, then select "Installed Plugins."
On the Installed Plugins page, locate "WPCode – Insert Headers and Footers + Custom Code Snippets."
Beneath the plugin's name, you will see its current version number.
If the version number displayed is earlier than 2.4.0 (for example, 2.3.9, 2.0, or any other version below 2.4.0), your site is vulnerable to CVE-2026-101301. If your plugin is version 2.4.0 or higher, it includes the patch for this vulnerability.
Regularly checking and updating your plugins is a fundamental security practice. This manual check provides a direct way to assess your site's status regarding this specific vulnerability.
What an attacker actually does
The WPCode plugin helps WordPress site administrators manage custom code snippets, including headers, footers, and other custom code. These snippets often add critical functionality, styling, or tracking scripts to a website. The plugin includes a "safe mode" feature, intended to prevent these snippets from executing on specific pages, such as the WordPress login screen, to avoid conflicts or unexpected behavior during authentication.
The vulnerability, identified as CVE-2026-101301, stems from an insufficient verification process within the wpcode_is_wplogin() function. This function is designed to determine if a request is genuinely targeting the WordPress login page. However, the flaw allows an unauthenticated attacker to send a request that includes a specific safe mode parameter. Because of the verification weakness, the plugin incorrectly interprets this request as being for the login page, even when it is not.
When the plugin mistakenly believes it is on a login page, it activates its safe mode. This action disables all automatically inserted snippets for that particular request. Consequently, the attacker can view the website without any of the custom JavaScript, CSS, or PHP code that the WPCode plugin normally injects. This could mean that analytics tracking scripts do not fire, custom styling is absent, or specific interactive elements relying on custom code do not function. The attacker effectively sees a version of the site stripped of its WPCode-managed enhancements, potentially aiding in reconnaissance or bypassing certain client-side protections. This vulnerability has a CVSS base score of 5.3, categorized as MEDIUM severity, with a vector of CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N. This indicates that the attack can be performed over the network, requires low complexity, no privileges, and no user interaction, resulting in a low impact on confidentiality for the attacker's session, but no impact on integrity or availability for the site as a whole.
How to detect a compromise
Detecting an attempt to exploit CVE-2026-101301 involves monitoring for specific patterns in your web server access logs. Since this vulnerability allows an attacker to temporarily suppress snippets for their own requests rather than gaining persistent access or modifying site files, detection focuses on identifying the attempts to trigger this behavior.
Review your web server access logs (e.g., Apache access_log, Nginx access.log) for requests that include the safe mode parameter. An attacker will send a request containing this parameter to activate the snippet suppression. Focus on requests from unauthenticated users, as legitimate administrators might use safe mode within the WordPress admin area for troubleshooting.
You can use command-line tools like grep to search these logs. For example, a command such as grep -i "wpcode_safe_mode" /var/log/apache2/access.log could help identify requests containing the safe mode parameter. Further refinement might involve excluding requests to the /wp-admin/ directory to narrow down unauthenticated attempts. For Nginx, the path might be /var/log/nginx/access.log.
Example grep command for Apache: grep -E "wpcode_safe_mode" /var/log/apache2/access.log | grep -v "/wp-admin/"
Example grep command for Nginx: grep -E "wpcode_safe_mode" /var/log/nginx/access.log | grep -v "/wp-admin/"
These commands search for lines containing "wpcode_safe_mode" and then filter out any lines that also contain "/wp-admin/", aiming to identify unauthenticated attempts outside the administrative interface.
Beyond direct log analysis, consider implementing a Web Application Firewall (WAF) that can detect and block requests with unusual or suspicious query parameters, especially those known to trigger vulnerabilities. While the immediate impact of this vulnerability is limited to the attacker's view of the site, repeated attempts to suppress snippets could indicate an attacker is performing reconnaissance. The CVSS vector for this vulnerability indicates a low impact on confidentiality (C:L) for the attacker's session, meaning they can observe the site without certain elements, but no impact on integrity (I:N) or availability (A:N) for other users or the site's overall operation. Therefore, detection focuses on identifying these reconnaissance attempts rather than looking for signs of data alteration or service disruption.
How to fix
The resolution for CVE-2026-101301 is to update the WPCode – Insert Headers and Footers + Custom Code Snippets – WordPress Code Manager plugin to version 2.4.0 or later. This updated version contains the necessary patch to correct the insufficient verification in the wpcode_is_wplogin() function, preventing unauthenticated attackers from bypassing snippet execution via safe mode.
Follow these steps to update your plugin:
Backup your website: Before performing any updates, create a complete backup of your WordPress site's files and database. This ensures you can restore your site if any unexpected issues arise during the update process.
Log in to your WordPress administration dashboard: Access your site's backend using your administrator credentials.
Navigate to the Plugins section: From the dashboard menu, go to "Plugins" and then select "Installed Plugins."
Locate the WPCode plugin: Find "WPCode – Insert Headers and Footers + Custom Code Snippets" in the list of installed plugins.
Initiate the update: If an update to version 2.4.0 or later is available, you will see a notification beneath the plugin's name, often stating "There is a new version of WPCode – Insert Headers and Footers + Custom Code Snippets available. View version 2.4.0 details or update now." Click on the "update now" link.
Verify the update: After the update process completes, refresh the "Installed Plugins" page and confirm that the WPCode plugin's version number is now 2.4.0 or higher.
If for any reason you do not see the update notification, you may need to manually check for updates by clicking the "Check for updates" link at the top of the "Installed Plugins" page, or temporarily deactivate and reactivate the plugin (though this is rarely necessary for standard updates). Ensuring your plugins are kept current is a critical component of maintaining WordPress site security.
Timeline
Date | Event |
|---|---|
2026-10-12 | WPScan publication |
2026-10-14 | NVD entry published |
2026-10-26 | PoC release scheduled |